First Aid for the USMLE Step 2 CS

Section 3. Minicases

Low Back Pain

Key History

Location, quality, intensity, radiation, context (moving furniture, bending/twisting, trauma), timing (disturbs sleep); associated symptoms (especially constitutional, incontinence); exacerbating and alleviating factors; history of cancer, recurrent UTIs, diabetes, renal stones, IV drug use, smoking.

Key Physical Exam

Vital signs; neurologic exam (especially L4-S1 nerve roots); back palpation and range of motion (although rarely of diagnostic utility); hip exam (can refer pain to the back); consider rectal exam.

Presentation

Differential

Workup

■ 45 yo F presents with low back pain that radiates to the lateral aspect of her left foot. The straight leg raise is positive. The patient is unable to tiptoe.

Disk herniation

Lumbar muscle strain

Tumor in the vertebral canal

XR—L-spine

MRI—L-spine

■ 45 yo F presents with low back pain that started after she cleaned her house. The pain does not radiate, and there is no sensory deficit or weakness in her legs. Paraspinal muscle tenderness and spasm are also noted.

Lumbar muscle strain

Disk herniation

Vertebral compression fracture

XR—L-spine

MRI—L-spine

■ 45 yo M presents with pain in the lower back and legs during prolonged standing and walking. The pain is relieved by sitting and leaning forward (eg, pushing a grocery cart).

Lumbar spinal stenosis

Lumbar muscle strain

Tumor in the vertebral

canal

Peripheral vascular disease

MRI—L-spine (preferred)

XR—L-spine

CT—L-spine

Ankle-brachial index

LOW BACK PAIN (cant'd)

Presentation

Differential

Workup

■ 17 yo M presents with low back pain that radiates to the left leg and began after he fell on his knee during gym class. He also describes areas of loss of sensation in his left foot. The pain and sensory loss do not match any known distribution. He insists on requesting a week off from school because of his injury.

Malingering

Lumbar muscle strain

Disk herniation

Knee or leg fracture Ankylosing spondylitis

XR—L-spine/knee

MRI—L-spine



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